1. Field of the Invention
The invention relates to a battery replacement system for an industrial truck having the following general features:                the industrial truck has an electrical propulsion drive,        the industrial truck has at least one battery compartment for holding a battery block,        the battery block can be moved essentially in the horizontal direction into the battery compartment or out of the battery compartment, and        an external holding apparatus, which is independent of the industrial truck, is provided for the battery block.        
2. Technical Considerations
Electrically powered industrial trucks are equipped with battery blocks which contain rechargeable batteries and can be charged either in the industrial truck or outside the industrial truck. If the charging process is carried out outside the industrial truck, the discharged battery block is removed from the industrial truck and can be replaced immediately by a freshly charged battery block. This allows the industrial truck to be used virtually around the clock. During the replacement process and during charging, the battery block is generally located on a holding apparatus which is matched to the battery block.
The battery block for an industrial truck can be replaced by means of a crane if the battery compartment is open at the top and the frame of the industrial truck and the fittings on it are designed appropriately. It is also known for the battery compartment to be provided with a side or front opening, through which the battery block can be pushed essentially in the horizontal direction out of the industrial truck. This horizontal removal of the battery block may, for example, be carried out by means of a lifting trolley equipped with an appropriate holding apparatus. It is also known for a roller path to be positioned alongside the opening in the battery compartment, onto which the battery block can then be pushed by hand or by means of an auxiliary apparatus.
Particularly in the case of relatively large industrial trucks having a correspondingly heavy battery block, manual movement of the battery block has been found to be difficult and dangerous. If auxiliary mechanical apparatuses are used to move the battery block, they must be able to apply a sufficiently high drive force and need to be designed in a correspondingly complex manner. This is true, in particular, when the battery block is anchored within the battery compartment such that the battery block must be lifted slightly in order to be able to subsequently move it horizontally.
The present invention is thus based on the object of providing a battery replacement system of the type mentioned initially but having a holding apparatus of simple design.